Carry-on electronics: the rules that vary and the ones that do not

This is less a set of instructions about flying with electronics than an argument, and it is worth saying so at the start.

The cabin rule is universal and non-negotiable

Spare lithium batteries and power banks must be carried in the cabin, because a fire in the hold cannot be reached. This applies to power banks regardless of size and to loose batteries of any chemistry that can short. Terminals in a bag can short against keys or coins, so taping them or using the original packaging is a genuine requirement rather than a formality.

A battery that is swollen, damaged or has been running hot should not be packed at all, and crew are trained to deal with one in the cabin precisely because nothing can be done about one in the hold.

Watt-hours, not milliamp-hours

International rules are written in watt-hours, and the common thresholds sit at 100Wh and 160Wh. Power banks are usually labelled in milliamp-hours, and converting requires multiplying by the cell voltage, typically 3.6 or 3.7 volts.

A 20,000mAh bank is therefore around 74Wh and comfortably under the first threshold, which is why most consumer banks are fine. Anything above 100Wh generally needs airline approval, and above 160Wh is usually refused.

Airlines add their own limits

Beyond the international framework, carriers cap the number of spare batteries and sometimes the total capacity per passenger. These limits are published and vary, and a bag full of camera batteries is where travellers most often exceed them.

Checking the specific carrier before a trip with substantial equipment takes two minutes and avoids losing it at the gate. Several carriers have gone further and now restrict using or charging a power bank in flight, or require it to stay visible rather than in an overhead bin, which is a recent enough rule that most passengers meet it for the first time on board.

Drones are a separate problem entirely

Some airlines refuse drones outright; others allow the aircraft but restrict the batteries. National regulations on import, registration and flying vary enormously, and confiscation on arrival is common in several countries. The rules that matter are those of the destination, not of your home country, and they change frequently.

Radio equipment more broadly is a customs question rather than an aviation one, and satellite messengers, long-range transmitters and some walkie-talkies are restricted or prohibited outright in a number of countries.

Devices in checked bags

Devices with installed batteries may generally be checked if switched fully off and protected from damage, but the guidance is to carry them. Some carriers require devices in checked baggage to be under a stated charge level. Anything valuable or fragile belongs in the cabin regardless of the rules, for entirely separate reasons.

The working rule: airline liability terms and most travel policies exclude electronics from checked baggage altogether, so a laptop crushed in the hold is generally nobody's loss but yours.

Getting through screening quickly

Packing electronics flat and in one layer helps the scanner resolve the image, whether or not removal is required. Keeping cables in a single pouch prevents the tangled mass that most reliably triggers a manual search. Where CT scanners are installed, removal is often no longer required, but the packing advice still holds.

Keeping enough charge to switch a device on matters too, since a laptop or phone that will not power up can be refused at some checkpoints and on some routes.

The takeaway

Batteries in the cabin, terminals protected, and convert to watt-hours before you pack.

Every kilo you leave behind pays you back at the third connection.